THE city’s luxury box at Shea Stadium was used almost entirely over the last four years by employees of the Parks Department – which oversees the ballpark – while other city agencies were largely shut out.

Documents obtained by The Post under the Freedom of Information Law show Parks workers were allocated 78 percent of the 324 Mets’ home games from 2005 to 2008 in the 15-seat box.

The Mayor’s Office and its subsidiaries grabbed 12 percent.

The rest of city government struck out with a meager 10 percent.

Mayoral aides have defended their hard-nosed negotiations in 2006 to secure luxury boxes valued at between $250,000 to $500,000 for the city in the new Met and Yankee stadiums, claiming they’re needed to reward municipal workers.

But insiders say many agencies weren’t aware free baseball tickets could be had for the asking.

“If people asked, they got them, but you had to know to ask,” a source said.

The 10,549 employees of the Correction Department didn’t get a single ticket. Neither did the 6,985 at the Administration for Children’s Services. The NYPD got to use the luxury box on one measly occasion, when the Mets faced the San Diego Padres on July 21, 2005.

The most eagerly sought tickets – the annual hometown Subway Series between the Mets and Yankees – always ended up in the hands of either Parks or the Mayor’s Office.

Officials say the ticket policy was overhauled last season, with a lottery established to level the playing field.